Acrylic-siloxane resin paint and painted article

ABSTRACT

A novel acrylic-siloxane paint binder resin that is crosslinkable with vinyl monomers by exposure to an electron beam is produced in a three step reaction wherein (1) a siloxane having two or more hydroxy or alkoxy functional groups per molecule is reacted with a C5 - C12 monohydroxy acrylate, i.e., the monohydroxy ester of a C2 - C8 diol and acrylic or methacrylic acid, (2) the siloxane-acrylate product of the first reaction step is reacted with a mixture of vinyl monomers at least one constituent monomer of which is selected from glycidyl acrylate and glycidyl methacrylate, and (3) the resultant siloxane-acrylate-vinyl monomer copolymer is reacted with a C5 C12 monohydroxy acrylate, i.e., the monohydroxy ester of a C2 C8 diol and acrylic or methacrylic acid.

United States Patent N ordstrom et al.

1 51 Mar. 21, 1972 [54] ACRYLIC-SILOXANE RESIN PAINT AND PAINTED ARTICLE[73] Assignee: Ford Motor Company, Dearborn, Mich. [22] Filed: Dec. 24,I969 [2]] Appl. No.: 888,056

521 u.s.c1 ..117/93.31, 117/124 F, 117/132 BS, 117/138.8 A, 117/148,117/161 ZA, 204/159.16,

51 1111.01 ..B44d 1/50 [58] Field otSearch ..117/93.31, 161 ZA, 132 13s,117/124 8, 138.8 A, 121, 148; 204/1s9.13, 159.16;

[56] References Cited UNITED STATES PATENTS 3,075,941 1/1963 Wynstra etal. ..1 17/132 BS 3,437,512 4/1969 Burlant et al. ..117/93.31

3,536,779 10/1970 Bedikian et al ..117/161 ZA Primary Examiner-Ralph S.Kendall Assistant Examiner-J. H. Newsome Att0rney-John R. Faulkner andOlin B. Johnson [5 7] ABSTRACT A novel acrylic-siloxane paint binderresin that is crosslinkable with vinyl monomers by exposure to anelectron beam is produced in a three step reaction wherein (1) asiloxane having two or more hydroxy or alkoxy functional groups permolecule is reacted with a C C monohydroxy acrylate, i.e., themonohydroxy ester of a C C diol and acrylic or methacrylic acid, (2) thesiloxane-acrylate product of the first reaction step is reacted with amixture of vinyl monomers at least one constituent monomer of which isselected from glycidyl acrylate and glycidyl methacrylate, and (3) theresultant siloxane-acrylate-vinyl monomer copolymer is reacted with a CC monohydroxy acrylate, i.e., the monohydroxy ester of a C C diol andacrylic or methacrylic acid.

17 Claims, No Drawings ACRYLIC-SILOXANE RESIN PAINT AND PAINTED ARTICLEBACKGROUND OF THE INVENTION Electron-curable, siloxane-modifiedpolyester paints have been disclosed by W.J/ Burlant and LH. Tsou'inU.S.Pat. Nos. 3,437,512 and 3,437,513. in oneembodiment, they produce thisresin by reacting a hydroxy'or hydrocarbonoxy functional siloxane with adiol and then reacting the siloxane-comprising product with twodifferent anhydrides, one of these being an alpha-beta olefinically'unsaturated compound, e.g., maleic anhydride, which introduces thedesired amount of alpha-beta olefinic unsaturation into the resin. Inanother embodiment, they produce the resin by reacting a hydroxylatedpolyester with a hydroxy or hydrocarbonoxy siloxane.

Electron-curable, siloxane-acrylate reaction products are disclosed incopending U.S. Pat. application Ser. No. 776,779 filed Nov. 18, 1968, byJohn D. Nordstrorn, coinventor herein. These materials are formed byreacting one molar part. hydroxy functional or hydrocarbonoxy functionalsiloxane with, preferably at least two molar' parts of, a hydroxylbearing ester of an alpha-beta, olefinically, unsaturated carboxylicacid.

it is one object of this invention to provide siloxane-comprisingacrylic paints curable by electron-beam radiation: which exhibitimproved adhesion to the substrate upon which they are cured.

It is another object of this invention to provide siloxanecomprisingacrylic paints curable by electron-beam radiation, which offer improvedweatherability and are more easily cured.

THE INVENTION It has been discovered that improved adhesion,weatherability, curability, and flexibility of paint film is obtained inan electron-beam cured coating comprising'in combination vinyl; monomersand a novel alpha-beta olefinically unsaturated acrylic-siloxane resinhereinafter described in detail. Thus, this invention relates to paintedTarticles of manufacture wherein the painted surface has high-resistanceto weathering, with theprocess of producing such painted surfaces, withthe paint used in such process, and with a method for manufactun ing thenovel paint binder resins used in said paintxln particu-, lar, thisinvention is concerned withthe painting ofsubstrates of wood, metal,glass, polymeric solids and fabrics of synthetic. or natural fibersand'the curing of the novel paints'thereon.

The novel acrylic-siloxane paint binder resin that: is used herein isformed by a three step reaction wherein l) a siloxane having two ormorehydroxy or a'lkoxy functional groups per molecule is reacted with a C, Cmonohydroxy acrylate, i.e., the monohydroxy ester of a C C diol andacrylic or' methacrylic acid, (2) the siloxane acrylate product of thefirstreaction step is reacted with a mixture of vinyl monomers having asa constituent monomer an acrylate selected from glycidyl acrylate andglycidyl methacrylate, and (3) the resultant siloxane-acrylate-vinylmonomer copolymer is reacted with a C C monohydroxy acrylate, i.e., themonohydroxy ester of a C C diol and acrylic or methacrylic acid.

In this application, the term paint" is meant to include pigment and/orfinely ground filler, the binder without pigment. and/or filler orhaving very "little ofthe same, which can be tinted if desired. Thus,the binder which is ultimately con-1 virtually all that is used toform'the film, or it can be a vehicle for pigment and/or particulatefiller material.

The siloxanes employed in the preparation of the binder have a reactivehydroxylor a C, to C.,,preferably C to C alkoxy group bonded to at leasttwo of its silicon atoms. The term siloxane as employed herein refers toa compound containing a verted to a durable film resistant to weatheringcan be all or! linkage, with the remaining valences being satisfied by ahydrocarbon radical, a hydrocarbonoxy radical, hydrogen, a hydroxy]group, or an oxygen atom which interconnects the silicon atom providingsuch valence with another silicon atom. The siloxane may be eithercyclic or acyclic. Suitable cyclic and acyclic siloxanes for use in thisinvention are described and illustrated in detail in the aforementionedpatents to WJ. Burlant and l. H. Tsou. The preferred siloxanes containtwo to five hydroxy and/or alkoxy functional groups. The choice ofreactants is advantageously arranged so that the siloxane comprisesabout ID to about 50 weight percent of the binder resin produced in thethree step reaction process.

The hydroxy acrylates used in the first reaction step are C, C esters ofa C C dihydric alcohol and acrylic or methacrylic acid. These include2-hydroxyethyl acrylate and methacrylate, 2-hydroxypropyl acrylate andmethacrylate, 2- hydroxybutyl acrylate and methacrylate, 2-hydroxyoctylacrylate and methacrylate, etc. A sufficient quantity of the hydroxyacrylate is used in the first reaction step to react with at least twoof the functional groups on the molecules of siloxane employed. In thepreferred embodiment, the quantity of hydroxy acrylate is sufficient toreact with all of the functional groups of the siloxane. The hydroxyacrylates used in the third reaction step may be the same as that usedin the first reaction step. Here enough of the hydroxy acrylate isemployed to react with a substantial amount, preferably all of theglycidyl molecules in the resin.

The vinyl monomers used in the second reaction step in- =clude as one ofthe constituent monomers an acrylate selected from glycidyl acrylate andglycidyl methacrylate. The glycidyl compound is in minor proportion,advantageously about 10 to 30 weight percent of this monomer mix. Themajor proportion 'The acrylic-siloxane resin thus produced is admixedwith C 5 C vinyl monomers to form a paint binder solution which is:applied by conventional means, e.g., spraying, roll coating, ,etc., toa substrate and polymerized thereon by ionizing radiation, preferably inthe form of an electron beam having average energy in the range of about100,000 to about 500,000 electron volts.

The vinyl monomers in which the acrylic-siloxane resin is dissolved toform the paint binder solution are preferably a mixture of acrylatesselected from esters of C C monohydric alcohols and acrylic ormethacrylic acid such as those above named. Vinyl hydrocarbons can beused alone but are preferably employed in minor proportion with a majorproportion of acrylates. Other acrylates such as the hydroxy acrylatesand methacrylates and di-, tri-, and tetrafunctional acrylates can beused in minor proportion. Also, in combination with the acrylates and/orvinyl hydrocarbons there can be used minor amounts of other vinylmonomers such as acrylonitrile, acrylamide, methacrylonitrile, vinylhalides, e. g., vinyl chloride, and vinyl carboxylates, e.g., vinylacetate.

betaolefinically unsaturated polymers may be substituted for a minorportion of the acrylic-siloxane resin of this invention.

The abbreviation Mrad" as employed herein means 1,000,000 rad. The termrad" as employed herein means that dose of radiation which results inthe absorption of 100 ergs of energy per gram of absorber, e.g., coatingfilm. The electron emitting means may be a linear electron acceleratorcapable of producing a direct current potential in the rangehereinbefore set forth. In such a device electrons are ordinarilyemitted from a hot filament and accelerated through a uniform voltagegradient. The electron beam, which may be about 5% inch diameter at thispoint, is then scanned in one direction to make a fan-shaped beam andthen passed through a metal window, e.g., aluminum, aluminum alloyedwith a small amount of copper, a magnesium-thorium alloy, etc., of about0.003 inch thickness.

The binder is preferably applied to the substrate and cured thereon as acontinuous film of substantially even depth, preferably a depth in therange of about 0.1 to about 4.0 mils depending upon the substrate andthe intended end use of the coated product. The film-forming bindersolution should have a viscosity low enough to permit rapid applicationto the substrate in substantially even depth and, preferably, highenough so that a 1 mil (0.001 inch) film will hold upon a verticalsurface without sagging. The viscosity of the binder is adjusted byvarying the molecular weight of the resin or resins and/or by varyingthe relative concentrations of the resin component and/or by varying therelative concentrations of dissimilar monomers within the vinyl monomercomponent. The binder is preferably applied to the substrate essentiallyfree of nonpolymerizable organic solvents and/or diluents but it iswithin the scope of this invention to employ such solvents and diluentsand to flash off the same prior to curing. The acrylicsiloxane resinsadvantageously have average molecular weight above about 2,500 and belowabout 50,000, preferably in the range of about 5,000 to about 25,000.

This invention will be more fully understood from the followingillustrative examples:

EXAMPLE I An acrylic-siloxane paint binder resin is prepared in thefollowing manner:

1. First step teaction-siloxane with hydroxy acrylate Reactants 8L AidsParts By Weight Siloxane" 206 Hydroxyethyl Acrylate 40 TetraisopropylTitanate 0.4

Hydroquinone l an acyclic polysiloxane having molecular weight in therange of 700 to 800 with an average of 3-4 methoxy functional groups permolecule.

Procedure:

The reactants are heated to I C. and from 100 to I50 C. over a 2-hourperiod and ll parts by weight methanol distillate are removed via aBarett distillation receiver.

2. Second step reactionsiloxane-acrylate with vinyl monomers Solution AReactants 8: Aids Parts By Weight Siloxane-Acrylate of l) 100 EthylAcrylate 43 Methyl Methacrylate 42 Glycidyl Methacrylate 23Azohisisobutyronitrile 5 Xylene 490 Solution B Reactants 8r Aids PartsBy Weight Hydroquinone 0.1 Methacrylic Acid l3 Tetraethyl AmmoniumChloride 0.5

Procedure Solution A is added to refluxing xylene. evenly, over a 2-hourperiod. The resultant solution is allowed to reflux for six hours. Theproduct has a nonvolatile content of 29 percent. Solution 8 is added tothe refluxing solution and heating is continued until the acid contentdrops to 0.053 milliequivalents per gram. (77 percent reaction). Thesiloxane-comprising product has a content of 0.5 units alpha-betaolefinic unsaturation per 1.000 units molecular weight.

. Third step reaction-siloxanemcrylateresin with hydroxy acrylateReactants Parts By Weight Product 0H2) 350 Hydroxyethyl Acrylate l7 Thereactants are heated to 130 C. and three parts by weight distillate areremoved in a Barrett receiver. The xylene is then removed by vacuumdistillation (10 mm. Hg, 1 10 C.) and the resin dissolved in 80 parts byweight of methyl methacrylate.

A film of the solution is applied to a metal substrate to an averagedepth of about 1 mil (0.001 inch) and exposed to an 8 Mrad close ofenergy from a 270 kilovolt, 25 milliampere electron beam in a nitrogenatmosphere. A hard, solvent resistant film results. This film has apencil hardness of F and withstands l3 rubs with a cloth soaked inmethyl ethyl ketone.

EXAMPLE 2 EXAMPLE 3 The procedure of Example 1 is repeated except forthe differences that the electron beam has average energy of 325kilovolts and films having average thickness of 0.2, 0.5, 1.5, 2.5 and 4mils are irradiated.

EXAMPLE 4 The procedure of Example 1 is repeated except for thedifferences that the substrate is wood and the vinyl monomer componentof the paint binder solution is a mixture of two molar parts methylmethacrylate and one molar part styrene.

EXAMPLE 5 The procedure of Example 1 is repeated except for thedifferences that the substrate is a synthetic polymeric solid, i.e.,acrylonitrile-butadiene-styrene copolymer, and the vinyl monomercomponent of the paint binder solution consists of two molar partsmethyl methacrylate, two molar parts ethyl acrylate, one molar partvinyl toluene and one-half molar part 2-ethylhexyl acrylate.

EXAMPLE 6 The procedure of Example 1 is repeated except for thedifferences that the substrate is glass, the vinyl monomer component ofthe paint binder solution consists of one molar part butyl acrylate, onemolar part ethyl acrylate and two molar parts styrene, and the paintbinder solution is pigmented with particulate titanium dioxide.

EXAMPLE 7 The procedure of Example 1 is repeated except for thedifferences that the substrate is cotton fabric, the acrylic-siloxaneresin component comprises weight percent of the filmforming solution, anequimolar amount of glycidyl acrylate is substituted for the glycidylmethacrylate in the second step reaction and the vinyl monomer componentis an equimolar mixture 'of methyl methacrylate, ethyl acrylate, and2-ethylhexyl acrylate.

EXAMPLE 8 The procedure of Example 1 is repeated except for thedifferences that the film-forming solution consists of 80 parts byweight of the acrylic-siloxane resin and 20 parts by weight methylmethacrylate,

The procedure of Example 1 is repeated'except that the methoxyfunctional acyclic siloxane is replaced with a hydroxy functional cyclicsiloxane (Dow Corning Z-60l8) having the following properties:

Hydroxy content, Dean Stark:

Percent condensable 5.5

Percent free 0.5 Average molecular weight 1,600 Combining weight 400Refractive index 1531-1 .539 Softening point, Durrans Mercury method, F.200

At 60% solids in sylene Specific gravity at 77 F. 1.075 Viscosity at 77F. centipoises 33 Gardner Holdt A-l A functionally equivalent amount ofthis siloxane is substituted for the siloxane of Example 1.

EXAMPLE 10 The procedure of Example 1 is repeated except for thedifferences that hydroxyethyl methacrylate is substituted for thehydroxyethyl acrylate in the first reaction step, hydroxybutyl acrylateis substituted for the hydroxyethyl acrylate of the third reaction stepand the paint binder solution comprises 65 weight percent resin and 35parts by weight methyl methacrylate.

EXAMPLE 1 l The procedure of Example 1 is repeated except for thedifferences that hydroxyoctyl acrylate is substituted for thehydroxyethyl acrylate in the first reaction step and the paint bindersolution comprises 35 parts by weight resin and 65 parts by weight ofavinyl monomer mixture of two molar parts methyl methacrylate, one molarpart ethyl acrylate and one molar part butyl methacrylate.

EXAMPLE 12 The procedure of Example 1 is repeated except for thedifference that the vinyl monomer component of the paint binder solutionconsists of three molar parts methyl methacrylate, one-fourth molar partvinyl chloride, one-fourth molar part vinyl acetate and one molar partstyrene.

EXAMPLE 13 The procedure of Example 1 is repeated except for thedifference that the vinyl monomer component of the paint binder solutionconsists of three molar parts methyl methacrylate, one-fourth molar partacrylonitrile, one-half molar part styrene and one-half molar-partdivinyl benzene.

EXAMPLE 14 The procedure of Example 1 is repeated except that the vinylmonomer component of the paint binder solution consists of three molarparts styrene and one molar part divinyl benzene.

It will be understood by those skilled in the art that changes can bemade in the foregoing examples without departing from the spirit andscope of this invention as expressed in the appended claims.

We claim:

1. An article of manufacture comprising a substrate and an adherentcoating of paint on an external surface thereof, said coating comprisingthe in situ formed polymerization product of a film-forming solution of20 to parts by weight vinyl monomers and 80 to 20 parts by weight of analpha-beta olefinically unsaturated acrylic-siloxane resin applied tosaid surface as a paint film and cross-linked thereon by exposing saidfilm to ionizing radiation, said acrylic-siloxane resin being formed by(l) reacting by etherification a siloxane having at least two functionalgroups with a hydroxy acrylate selected from the monohydroxy esters of CC dihydric alcohols and acrylic or methacrylic acid, (2) reacting byvinyl addition the resultant siloxane-acrylate with a mixture of vinylmonomers having as a constituent monomer an acrylate selected fromglycidyl acrylate and glycidyl methacrylate and (3) reacting byetherification with the glycidyl functionality the resultantsiloxane-comprising resin with a hydroxy acrylate selected frommonohydroxy esters of C2- C dihydric alcohols and acrylic or methacrylicacid.

2. An article of manufacture in accordance with claim 1 wherein saidsiloxane comprises about 10 to about 50 weight percent of said acrylicsiloxane resin.

3. An article of manufacture in accordance with claim 1 wherein saidfilm-forming solution consists essentially of 35 to 65 parts by weightof said acrylic-siloxane resin and 65 to 35 parts by weight of vinylmonomers.

4. An article of manufacture in accordance with claim 1 wherein saidsubstrate is metal.

5. An article of manufacture in accordance with claim 1 wherein saidsubstrate is wood.

6. An article of manufacture in accordance with claim 1 wherein saidsubstrate is a synthetic polymeric solid.

7. An article of manufacture in accordance with claim 1 wherein saidsubstrate is glass.

8. An article of manufacture in accordance with claim 1 wherein saidsubstrate is fabric.

9. An article of manufacture in accordance with claim 1 wherein saidsiloxane contains an average of two to five of said functional groupsper molecule.

10. A paint comprising particulate pigment and a film-forming solutionconsisting essentially of 20 to 80 parts by weight vinyl monomers and 80to 20 parts by weight of an acrylicsiloxane resin formed by 1) reactingby etherification a siloxane having at least two functional groupsselected from hydroxyl groups and alkoxy groups with a hydroxy acrylateselected from the monohydroxy esters of C C dihydric alcohols andacrylic or methacrylic acid, (2) reacting by vinyl addition theresultant siloxane-acrylate with a mixture of vinyl monomers having as aconstituent monomer an acrylate selected from glycidyl acrylate andglycidyl methacrylate and (3) reacting by etherification with theglycidyl functionality the resultant siloxane-comprising resin with ahydroxy acrylate selected from monohydroxy esters of C C dihydricalcohols and acrylic or methacrylic acid.

11. A paint in accordance with claim 10 wherein said functional groupsare hydroxyl groups and said siloxane contains two to five of saidgroups per molecule.

12. A paint in accordance with claim 10 wherein said functional groupsare methoxy groups and said siloxane contains two'to five of said groupsper molecule.

13. A paint in accordance with claim 10 wherein said filmforrningsolution consists essentially of 35 to 65 parts by weight vinyl monomersand 65 to 35 parts by weight of said acrylic-siloxane resin.

14. A paint in accordance with claim 10 wherein said vinyl monomersconsist essentially of esters of acrylic or methacrylic acid and a C,-Cmonohydric alcohol.

15. A paint in accordance with claim 10 wherein said vinyl monomersconsist essentially of a mixture of C C, vinyl hydrocarbons and estersof acrylic or methacrylic acid and a C C monohydric alcohol.

16. A method for coating a substrate which comprises applying to thesurface of said substrate to an average depth in the range of about 0.1to about 4 mils a film-forming solution consisting essentially of 20 to80 parts by weight vinyl monomers and 80 to 20 parts by weight of anacrylic-siloxane resin and cross-linking said vinyl monomers and saidresin upon said surface by exposing said coating to an electron beamhaving average energy in the range of about 100,000 to about 500,000electron volts, said acrylic-siloxane resin being formed by (1) reactingby etherification a siloxane having at least two functional groupsselected from hydroxy] groups and alkoxy groups with a hydroxy acrylateselected from the monohydroxy esters of C C dihydric alcohols andacrylic or methacrylic acid, (2) reacting by vinyl addition theresultant siloxane-acrylate with a mixture of vinyl monomers having as aconstituent monomer an acrylate selected from glycidyl acrylate andglycidyl methacrylate and (3) reacting by etherification with theglycidyl functionality the resultant siloxane-comprising resin with ahydroxy acrylate selected from monohydroxy esters of C -C dihydricalcohols and acrylic or methacrylic acid.

17. An acrylic-siloxane resin formed by (l) reacting by etherification asiloxane having at least two functional groups selected from hydroxy]groups and alkoxy groups with a hydroxy acrylate selected from themonohydroxy esters of C, C dihydric alcohols and acrylic or methacrylicacid, (2) reacting by vinyl addition the resultant siloxane-acrylatewith a mixture of vinyl monomers having as a constituent monomer anacrylate selected from glycidyl acrylate and glycidyl methacrylate and(3) reacting by etherification with the glycidyl functionality theresultant siloxane-comprising resin with a hydroxy acrylate selectedfrom monohydroxy esters of C C dihydric alcohols and acrylic ormethacrylic acid.

2. An article of manufacture in accordance with claim 1 wherein saidsiloxane comprises about 10 to about 50 weight percent of said acrylicsiloxane resin.
 3. An article of manufacture in accordance with claim 1wherein said film-forming solution consists essentially of 35 to 65parts by weight of said acrylic-siloxane resin and 65 to 35 parts byweight of vinyl monomers.
 4. An article of manufacture in accordancewith claim 1 wherein said substrate is metal.
 5. An article ofmanufacture in accordance with claim 1 wherein said substrate is wood.6. An article of manufacture in accordance with claim 1 wherein saidsubstrate is a synthetic polymeric solid.
 7. An article of manufacturein accordance with claim 1 wherein said substrate is glass.
 8. Anarticle of manufacture in accordance with claim 1 wherein said substrateis fabric.
 9. An article of manufacture in accordance with claim 1wherein said siloxane contains an average of two to five of saidfunctional groups per molecule.
 10. A paint comprising particulatepigment and a film-forming solution consisting essentially of 20 to 80parts by weight vinyl monomers and 80 to 20 parts by weight of anacrylic-siloxane resin formed by (1) reacting by etherification asiloxane having at least two functional groups selected from hydroxylgroups and alkoxy groups with a hydroxy acrylate selected from themonohydroxy esters of C2 - C8 dihydric alcohols and acrylic ormethacrylic acid, (2) reacting by vinyl addition the resultantsiloxane-acrylate with a mixture of vinyl monomers having as aconstituent monomer an acrylate selected from glycidyl acrylate andglycidyl methacrylate and (3) reacting by etherification with theglycidyl functionality the resultant siloxane-comprising resin with ahydroxy acrylate selected from monohydroxy esters of C2 - C8 dihydricalcohols and acrylic or methacrylic acid.
 11. A paint in accordance withclaim 10 wherein said functional groups are hydroxyl groups and saidsiloxane contains two to five of said groups per molecule.
 12. A paintin accordance with claim 10 wherein said functional groups are methoxygroups and said siloxane contains two to five of said groups permolecule.
 13. A paint in accordance with claim 10 wherein saidfilm-forming solution consists essentially of 35 to 65 parts by weightvinyl monomers and 65 to 35 parts by weight of said acrylic-siloxaneresin.
 14. A paint in accordance with claim 10 wherein said vinylmonomers consist essentially of esters of acrylic or methacrylic acidand a C1-C8 monohydric alcohol.
 15. A paint in accordance with claim 10wherein said vinyl monomers consist essentially of a mixture of C8-C10vinyl hydrocarbons and esters of acrylic or methacrylic acid and a C1-C8monohydric alcohol.
 16. A method for coating a substrate which comprisesapplying to the surface of said substrate to an average depth in therange of about 0.1 to about 4 mils a film-forming solution consistingessentially of 20 to 80 parts by weight vinyl monomers and 80 to 20parts by weight of an acrylic-siloxane resin and cross-linking saidvinyl monomers and said resin upon said surface by exposing said coatingto an electron beam having average energy in the range of about 100,000to about 500,000 electron volts, said acrylic-siloxane resin beingformed by (1) reacting by etherification a siloxane having at least twofunctional groups selected from hydroxyl groups and alkoxy groups with ahydroxy acrylate selected from the monohydroxy esters of C2C8 dihydricalcohols and acrylic or methacrylic acid, (2) reacting by vinyl additionthe resultant siloxane-acrylate with a mixture of vinyl monomers havingas a constituent monomer an acrylate selected from glycidyl acrylate andglycidyl methacrylate and (3) reacting by etherification with theglycidyl functionality the resultant siloxane-comprising resin with ahydroxy acrylate selected from monohydroxy esters of C2-C8 dihydricalcohols and acrylic or methacrylic acid.
 17. An acrylic-siloxane resinformed by (1) reacting by etherification a siloxane having at least twofunctional groups selected from hydroxyl groups and alkoxy groups with ahydroxy acrylate selected from the monohydroxy esters of C2 - C8dihydric alcohols and acrylic or methacrylic acid, (2) reacting by vinyladdition the resultant siloxane-acrylate with a mixture of vinylmonomers having as a constituent monomer an acrylate selected fromglycidyl acrylate and glycidyl methacrylate and (3) reacting byetherification with the glycidyl functionality the resultantsiloxane-comprising resin with a hydroxy acrylate selected frommonohydroxy esters of C2 - C8 dihydric alcohols and acrylic ormethacrylic acid.